Question: What do the following two equations represent? $2x-y = 5$ $x+2y = 1$
Putting the first equation in $y = mx + b$ form gives: $2x-y = 5$ $-y = -2x+5$ $y = 2x - 5$ Putting the second equation in $y = mx + b$ form gives: $x+2y = 1$ $2y = -x+1$ $y = -\dfrac{1}{2}x + \dfrac{1}{2}$ The slopes are negative inverses of each other, so the lines are perpendicular.